Characterization of optical distortion in a head mounted display

Abstract

An optical profiling system characterizes distortion of a head-mounted display (HMD) under test. The optical profiling system includes a camera assembly and a controller. The controller provides presenting instructions that cause the HMD under test to present test patterns and also provides imaging instructions that cause the camera assembly to captures images of the test patterns presented by the HMD under test. The camera assembly includes one or more characterization cameras. A characterization camera is configured to mimic movement of a human eye and is positioned in an eye box region of the HMD under test. Using the images captured by the camera assembly, the controller measures distortion of the HMD under test. The controller may generate a report charactering the HMD under test based on the measured distortion.

What is claimed is: 
     
       1. An optical profiling system comprising:
 a camera assembly including a characterization camera configured to capture one or more images of content presented by a head-mounted display (HMD) under test in accordance with imaging instructions, the characterization camera positioned in an eye box region of the HMD under test and configured to imitate movement of a human eye; and 
 a controller configured to:
 generate the imaging instructions, the imaging instructions describing one or more positions of the characterization camera and providing instruction for a number of exposures at each of the one or more positions, 
 instruct the HMD under test to present a test pattern, 
 provide the imaging instructions to the camera assembly, and 
 measure distortion of one or more optical elements in the HMD under test using one or more images captured by the camera assembly. 
 
 
     
     
       2. The optical profiling system of  claim 1 , wherein the controller is further configured to:
 generate a report characterizing the one or more optical elements based on the measured distortion; and 
 provide the report to a user of the HMD under test. 
 
     
     
       3. The optical profiling system of  claim 1 , wherein the controller is further configured to:
 determine whether the HMD under test is qualified based on the measured distortion; and 
 provide the determination to a user of the HMD under test. 
 
     
     
       4. The optical profiling system of  claim 1 , wherein the characterization camera comprises a plurality of color filters that selectively filter out different colors from the content in accordance with imaging instructions. 
     
     
       5. The optical profiling system of  claim 1 , wherein the controller is further configured to generate the imaging instructions based at least in part on received input parameters, and the received input parameters identify one or more types of human eye movements. 
     
     
       6. The optical profiling system of  claim 5 , wherein a type of human eye movement is selected from a group consisting of: eye rotation, saccade, smooth pursuit movement, vergence movement, and vestibulo-ocular movement. 
     
     
       7. The optical profiling system of  claim 1 , wherein the controller is further configured to:
 instruct the HMD under test to present a test pattern based at least in part on received input parameters. 
 
     
     
       8. The optical profiling system of  claim 7 , wherein the received input parameters identify at least one of the one or more types of distortions to measure. 
     
     
       9. The optical profiling system of  claim 1 , wherein measuring distortion of the one or more optical elements comprises assessing at least one of the following: resolution, illumination uniformity, color variation, focus differentiation, chromatic aberration, spherical aberration, astigmatism, and field curvature. 
     
     
       10. The optical profiling system of  claim 1 , wherein the characterization camera is configured to imitate movement of the human eye in at least three degrees of freedom. 
     
     
       11. An optical profiling system comprising:
 a camera assembly comprising:
 a first characterization camera configured to capture one or more images of content presented by a head-mounted display (HMD) under test in accordance with first imaging instructions, the first characterization camera positioned in a first eye box region of the HMD under test and configured to imitate movement of a first human eye, and 
 a second characterization camera configured to capture one or more images of content presented by the HMD under test in accordance with second imaging instructions, the second characterization camera positioned in a second eye box region of the HMD under test and configured to imitate movement of a second human eye; and 
 
 a controller configured to:
 generate the first and second imaging instructions, the first imaging instructions describing one or more positions of the first characterization camera and providing instruction for a number of exposures at each of the one or more positions of the first characterization camera, and the second imaging instructions describing one or more positions of the second characterization camera and providing instruction for a number of exposures at each of the one or more positions of the second characterization camera, 
 instruct the HMD under test to present a test pattern, 
 provide the first and second imaging instructions to the camera assembly, and 
 measure distortion of one or more optical elements in the HMD under test using one or more images captured by the camera assembly. 
 
 
     
     
       12. The optical profiling system of  claim 11 , wherein the first imaging instructions and the second imaging instructions include a plurality of positions for the first characterization camera and corresponding positions for the second characterization camera that correspond to different inter-pupillary distance values. 
     
     
       13. The optical profiling system of  claim 11 , wherein the controller is further configured to:
 generate a report characterizing the one or more optical elements based on the measured distortion; and 
 provide the report to a user of the HMD under test. 
 
     
     
       14. The optical profiling system of  claim 11 , wherein the controller is further configured to:
 determine whether the HMD under test is qualified based on the measured distortion; and 
 provide the determination to a user of the HMD under test. 
 
     
     
       15. The optical profiling system of  claim 11 , wherein the controller is further configured to:
 generate the first and second imaging instructions based at least in part on received input parameters. 
 
     
     
       16. The optical profiling system of  claim 15 , wherein the received input parameters identifies one or more types of human eye movements. 
     
     
       17. The optical profiling system of  claim 16 , wherein a type of human eye movement is selected from a group consisting of: eye rotation, saccade, smooth pursuit movement, vergence movement, and vestibulo-ocular movement. 
     
     
       18. The optical profiling system of  claim 11 , wherein the controller is further configured to:
 instruct the HMD under test to present a test pattern based at least in part on received input parameters. 
 
     
     
       19. The optical profiling system of  claim 18 , wherein the received input parameters identify at least one of the one or more types of distortions to measure. 
     
     
       20. The optical profiling system of  claim 11 , wherein measuring distortion of the one or more optical elements comprises assessing at least one of the following: resolution, illumination uniformity, color variation, focus differentiation, chromatic aberration, spherical aberration, astigmatism, and field curvature.